This invention relates generally to a process for controlling the planning and implementation of a blasting system.
Blasting systems vary substantially inter alia in respect of the techniques and technologies which are employed. A large mining operation for example will typically make use of electronic detonators and software-based design systems. However, in a relatively small mine of quarry, this type of approach may not be justified. There may also be a shortage of personnel who are sufficiently qualified or who are prepared to make use of a high level approach in planning and implementing a blasting system.
As a consequence many small mines and quarries operate on basic systems and do not make use of the complex and sophisticated techniques which are available and which are generally used in large scale mining and rock breaking applications.
Consequently, to a substantial extent the planning of a blasting system in a small mine is based on experience and generic factors. Typically an area of a blast bench is surveyed, and marked by a planner or surveyor. Subsequently a blast planning and design process is carried out by a blaster who proceeds on the basis of experience and knowledge of blasts previously conducted at the site to achieve desired results in respect of overburden removal, fragmentation of an ore body e.g. a coal seam, fragmentation of rock and so on.
In many instances there is no predetermined blast plan. Borehole locations are often determined on a “best guess” basis and are marked using rudimentary procedures such as tape measures, guide ropes, pacing of distances etc. The borehole locations are marked and, subsequently, a blaster manually directs a drill rig to each hole location.
Some hole locations, may be altered, or added to an initial system, depending on the outcome of boreholes which have been drilled. Manual observations are made with drill, swarf and the depth of each borehole is manually checked to establish some guideline of satisfactory process. Detonators and boosters, depending from shock tubes, are placed at an appropriate depth in the individual boreholes. Typically each shook tube is secured at ground level with the detonator and booster suspended from the shock tube. A suitable quantity of explosive emulsion is pumped from a delivery vehicle into each borehole. Manual techniques are used to ensure that the borehole has been correctly charged with the emulsion. Thereafter the emulsion is left to gas and, once the emulsion has solidified, the quantity of the explosive in each borehole is again cheeked. As may be appropriate, additional emulsion is added, whereafter stemming, in the form of swarf, is placed over the emulsion in the borehole. Stemmed holes are then interconnected to achieve a desired blast layout. Wiring to an initiating point takes place and the blast is ready.
It is apparent from the aforegoing that the establishment of a blasting system in this way is almost wholly dependent on experience and manually implemented techniques and, inevitably, is prone to human error. Nonetheless due to a variety of factors the use of more sophisticated techniques may not be justifiable.
Problems which are associated with the aforegoing include the following:                a) a variation in the process, or the omission of a stage, can compromise the blast result and pose operational and safety risks;        b) blasts are not necessarily optimized to achieve maximum rock displacement or breakage; and        c) processes are not normally well documented and there may be little or no correlation between outcome and intent.        
Consequently, although a small operation may be functioning under tight financial constraints, an inefficient outcome of a manually planned and implemented blasting system can compound operational and financial pressures.
An object of the present invention is to provide a method of planning and implementing a blasting system which, to a substantial extent, can address the aforementioned factors and which does not make use of sophisticated electronic blasting and software-based design systems.